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3 GROUNDWATER MONITORING RESULTS <br /> Groundwater elevation data, and analytical results are discussed in this section <br /> Laboratory analytical reports are contained in Appendix 1 <br /> 3.1 Groundwater Elevation Data <br />' Groundwater elevations measured in site monitoring wells on October 18, <br /> 2000 (summarized in Table 1), ranged from minus (-) 22 65 feet to—23 36 <br /> feet MSL Groundwater levels in the wells decreased approximately 2 5 feet <br /> from the previous July 2000 monitoring event As shown in Figure 3, the <br /> groundwater flow direction is easterly at a gradient of about 2 3 x 10"3 feet per <br /> foot, which is consistent with historic trends <br /> 3.2 BTEX and TPH-G Analytical Results <br /> Petroleum hydrocarbon compounds were detected in groundwater samples <br /> collected from wells MW-1, MW4, MW-12, SP-1, SP-2, PZ-1, and PZ-2 <br /> The highest BTEX concentrations appear to be centered in the vicinity of the <br /> former gasoline USTs near wells MW-1, SP-1, and PZ-1 (see Figure 4) There <br /> were no detectable petroleum hydrocarbon concentrations measured in <br /> samples from wells MW-9, MW-10, and MW-13 <br /> Detected benzene concentrations ranged from 33 gg/l, in the sample collected <br /> from well SP-2, to 4,600 µg/1 in the sample from PZ-1 Toluene ranged from <br /> 3 1 gg/l, in the sample from MW-4, to 5,200 µg/1 in the sample from PZ-1 <br />' Ethylbenzene ranged from 1 3 gg/l, in the sample from MW-4, to 1,600 µg/1 <br /> in the sample from PZ-1-1 Xylenes ranged from 17 gg/l, in the sample from <br /> MW-4, to 6,100 µg/1 in the sample from PZ-1 <br />' As shown in Table 4,the BTEX concentrations measured in the current PZ-1 <br /> sample are spiked relatively higher than those measured in samples collected <br /> during the three previous quarters However, the BTEX concentrations this <br /> quarter are consistent with concentrations measured one year ago <br />' Higher TPH-G concentrations are centered near the former gasoline USTs <br /> (Figure 5) TPH-G concentrations were measured in the MW-1, SP-1, PZ-1, <br /> and PZ-2 samples at concentrations of 16,000 µg/1, 26,000 gg/l, 35,000 µg/1, <br />' and 17,000 µg/1, respectively <br />■ 8 <br /> October 2000 <br /> Groundwater Monitonng Report <br /> The Earthgralns Company <br /> 2651 South Airport Way <br /> Stockton,California <br /> Prepared for THE EARTHGRAINS COMPANY Prepared by Philip Services Corp <br />' H 1ENW7400137.1121382EG15tocktonVStockton1100pmon doc November 10,2000 <br />